In developed countries, recently, damage of a flood disaster such as an overflow or a flood is decreasing as the construction of infrastructures progresses. In developing countries, however, the construction of infrastructures is insufficient, and flood disasters readily occur, as compared to the developed countries.
Especially in a district of a developing country where economic activities concentrate as in a developed country, the risk of human damage and economic damage caused by a flood disaster is high, and there is an adverse effect on the economic growth.
On the other hand, there is known a technology of forecasting a flood using water-associated information in a place where a river may overflow and metrological information from the Meteorological Agency to protect a region from a flood disaster such as an overflow or a flood.
In a developed country, since the infrastructures are constructed, as described above, it is possible to easily collect water level information of a river and the like and relatively correctly predict a flood. However, in a developing country, it is not easy to collect various kinds of information, and it is impossible to correctly predict a flood.
Hence, particularly in a developing country, since the infrastructures are not constructed, it is difficult to correctly predict a flood. For this reason, the environment readily suffers human damage and economic damage, and a disaster prevention system capable of taking an effective measure against a flood disaster has been demanded.